[gtk/ebassi/gidocgen] progressbar: Use markdown for css tree

[Matthias Clasen <matthiasc src gnome org>]

commit 6ca13a4f129b4bf5ae394fa999d047c918825e7c
Author: Matthias Clasen <mclasen redhat com>
Date:   Sat Feb 27 20:04:37 2021 -0500

    progressbar: Use markdown for css tree

 gtk/gtkprogressbar.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/gtk/gtkprogressbar.c b/gtk/gtkprogressbar.c
index 53121f32ef..4517a85ba5 100644
--- a/gtk/gtkprogressbar.c
+++ b/gtk/gtkprogressbar.c
@@ -68,12 +68,12 @@
  *
  * # CSS nodes
  *
- * |[<!-- language="plain" -->
+ * ```
  * progressbar[.osd]
  * ├── [text]
  * ╰── trough[.empty][.full]
  *     ╰── progress[.pulse]
- * ]|
+ * ```
  *
  * `GtkProgressBar` has a main CSS node with name progressbar and subnodes with
  * names text and trough, of which the latter has a subnode named progress. The